The present invention relates to a damper element for damping pressure pulsations in vehicle fuel systems.
In gasoline fuel injection systems, such as manifold injection systems, pressure pulsations within the fuel system can cause various problems. For example, internal pressure pulsations within a fuel rail tube of an automotive gas multi-port fuel injection system can result in audible noise, and can adversely affect tailpipe emissions and driveability. Various solutions have been proposed to solve these problems including conventional diaphragm dampers.
The present invention provides a low-cost damper element which has good durability even in environments in which it is exposed to fuel and fluctuating temperatures. The damper element damps pressure pulsations in a flow discharge medium. Preferably, the damper element is employed to damp pressure pulsations in a fuel system such as in fuel rails of internal combustion engines.
The invention also provides a simple method of manufacturing the damper. The method includes shaping and sealing a metallic tube. More specifically, the method includes the steps of: rolling a ribbon of metal into a tube; welding the longitudinal seam; and sealing the ends.
Preferably, the tube initially has a circular cross-section, and is formed into a desired cross-section, such as oval or rectangular, after the longitudinal seam is in place. Preferably, the tube is cut to a desired length, the ends are flattened, and then the ends are sealed by laser or resistance welding. Preferably, wire support members are clipped onto the flattened ends of the tube. Alternatively, the wire support members are welded or brazed to the flattened ends of the tube. The wire supports can include stainless steel wire. If brazing is used, the wire support members can include copper-coated stainless steel wire, and the copper coating may be used as the braze media. Preferably, a gas is introduced into the interior of the tube before flattening and sealing the ends of the tube.
A damper element formed by the above method may be made from a single piece of metal and preferably has a longitudinal seam along only one side of the damper element. The method is generally less expensive than prior art methods for making a clam-shell type damper element. Such prior art methods generally include welding two pieces of metal together and forming a seam around the entire perimeter of the damper element. Also, the damper element of the present invention is generally less prone to failure due to the single longitudinal seam.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.